1. Field of the Invention
The invention relates generally to the field of photography, and in particular to a film cassette having frangible means for preventing rotation of a film spool inside the cassette and to a camera device that breaks the frangible means to permit rotation of the film spool.
2. Description of the Prior Art
Prior art U.S. Pat. No. 3,784,001, issued Jan. 8, 1974, discloses a film cassette in which there is a frangible connection between a film spool and an internal wall of the cassette shell. The frangible connection has sufficient strength to prevent the film spool from rotating during handling of the film cassette prior to use but which will break when a filmstrip wound on the spool is pulled from the shell. Since the frangible connection is located inside the shell, there is no way of knowing when it is broken.
Prior art U.S. Pat. No. 4,683,870, issued Jul. 28, 1987, discloses a film cassette in which a film spool has a coaxial opening containing a frangible piece. When the film cassette is loaded into an associated camera, a shaft is received in the coaxial opening to fracture the frangible piece and thereby provide an indication the cassette was used. No means exists, however, for preventing rotation of the film spool during handling prior to use.